malt pipe question

[Moog]

can someone advise me what is the ideal width gaps to use for a malt pipe to give good drainage without letting bits of grain get through into the wort,

 

[Lyrebird_Cycles]

It depends on the the percent open space of the lauter plate and the depth of the bed above it.

My latest one was 300mm high and had 0.6mm gaps for 6% open area. This seems to run a little fast on an all barley mash so my brewhouse efficiency has dropped to ~88%. It seemed to work well on a recent part rye mash which I attribute to the higher viscosity.

Currently building one which will be 450mm high with 0.5mm gaps for 4% open area, hoping this will slow the runnings down enough to get better efficiency.

 

[good4whatAlesU]

Slightly OT but was doing the washing up the other day and I was eyeing off the kitchen sink thinking.. hmmm the SS drain grooves on this might work for something...

 

[BrockHops]

View attachment 108042Slightly OT but was doing the washing up the other day and I was eyeing off the kitchen sink thinking.. hmmm the SS drain grooves on this might work for something...

I look at everything and think "hmm, that could be good for brewing/fermenting"

It's a disease.

 

[Moog]

mmmmm. i'll post pics later, but I had a tank/malt pipe made to replace my basket (BIAB) to negate the need for a brew bag... I had the bottom plate lazer cut with 0.2mm slits (lots of them) and after the last 3 or 4 brews, I've done a dummy test run with that MP to test the drainage, re-using my spent grain in hot tap water, but I've not been confident to give it a go, without a drainage problem, each time I've separated the gaps more, and more, I'm loosing faith in the whole idea, but clinging on to the no washing, ready to go brew equipment idea...

 

[Stouter]

I'm keen to see this Moog.
I've been thinking about a malt pipe for the urn but wasn't sure where to start. The bag isn't a huge effort to wash but my process is long, to rinse the bits of extra caught up grain, soak in sodium percarb, rinse in hot water, then dry on the clothesline, then shake out. It doesn't hurt to look at ways to streamline.
Please share.

 

[Moog]

here's my current basket on the left, and the malt pipe on the right, you can see from the close up pic how the slits were to start with, The holes were about 7.5% of the area.
Then to help drainage I bent every other one down, to give about a 1.5mm gap.
I'm still not fully happy with drainage.
I filled the tank with 60L of hot tap water (55*C), and then filled it with the spent grain.
I lifted the malt pipe, and it seemed to drain ok, then I dropped it back down to give it a second go, this time the drainage seem much worse.
Not too sure why that was....
When it had fully drained, I drained off some of the trial wort, to check for particles.
It didn't seem too bad.
When I finished draining the tank, there was some fine stuff left over, but not really enough to worry about.

 

[Stouter]

Geez that's a lot of work gone into that, very nice.

 

[husky]

FYI I have had a FB quoted in wedgewire by a company who supplies a lot of breweries and they have spec'd up a 23.5% open area FB with 0.7mm opening slots.
I have made quite a few FB's in perf sheet and have always gone for the 20-25% open area with no issues. I do use a diaphragm valve to slow the runnings down when required, but usually gravity is fine.

 

[Moog]

OK, thanks, that's good info.... I'm using it in BIAB, but I hoist very, very slowly to create a proper grain bed, and it works well, with the current basket set up.
I'm just concerned about a stuck mash on a brew day if my gaps aren't large enough.